[GitHub] [incubator-druid] clintropolis commented on a change in pull request #7729: SeekableStreamIndexTaskRunner: Lazy init of runner.

[GitBox <gi...@apache.org>]

clintropolis commented on a change in pull request #7729: SeekableStreamIndexTaskRunner: Lazy init of runner.
URL: https://github.com/apache/incubator-druid/pull/7729#discussion_r286673679
 
 

 ##########
 File path: indexing-service/src/main/java/org/apache/druid/indexing/seekablestream/SeekableStreamIndexTask.java
 ##########
 @@ -283,13 +282,20 @@ public boolean withinMinMaxRecordTime(final InputRow row)
   @VisibleForTesting
   public Appenderator getAppenderator()
   {
-    return runner.getAppenderator();
+    return getRunner().getAppenderator();
   }
 
   @VisibleForTesting
   public SeekableStreamIndexTaskRunner<PartitionIdType, SequenceOffsetType> getRunner()
   {
+    if (runner == null) {
+      synchronized (runnerInitLock) {
+        if (runner == null) {
+          runner = createTaskRunner();
+        }
+      }
+    }
 
 Review comment:
   guava has `Suppliers.memoize` that does this, we use it in a couple of places already

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